Cannot Delete Original User Account in Refurbished Win 7 Laptop

I recently purchased an HP 8460p Win 7 Pro 64 bit refurbished laptop that came with Windows already installed and configured to run under User name, hp.
I would like to change the User name to CAG. Therefore, I went to User Accounts then to the Control Panel, clicked on Manage Another Account and created User Account, CAG. Next, I shut down the computer, restarted and signed in under CAG, and when I did this, I found a folder had been created on my System partition for user, CAG with sub accounts.

Next, I clicked on Administrative Tools/Computer Management and under Local Users and Groups I found user, CAG with a path to home folder, C/Users?CAG. Everything seemed cool except that I needed to delete hp. So I copied the contents of hp's sub folders to CAG and tried to delete hp. When I clicked on Delete, I was told I needed Administrative Rights to delete the folder. That was over one week ago. I am still trying to obtain the Administrative right to delete hp.
Can anyone help me?

Welcome to the forum you will have to take ownership of the folder and sub folders did you delete the actual account as that normally gives an option to delete files.Are you sure the new account is administrator before you get into trouble

The way to delete an account is to go to Control Panel\All Control Panel Items\User Accounts\Manage Accounts click on your account than mange another accout select Hp and delete - delete files

samuria said:

Welcome to the forum you will have to take ownership of the folder and sub folders did you delete the actual account as that normally gives an option to delete files.Are you sure the new account is administrator before you get into trouble

I did all of the above and when I start up the computer, it reverts back to the original owner.
CAG43

As you'll never know what has been installed on a refurbished computer, I'll suggest you to do a Factory Recover.
It will format the HDD and load a Windows as it was released from HP.
HP PCs - Performing an HP System Recovery (Windows 7) | HP(R) Customer Support

In response to AddRam,
I copied the contents of hp into my user account in hopes that I could then, delete hp.
Also, I was able to make myself the administrator/owner with no problem which is why I cannot understand hp still remaining on the hard drive as Ztrucker asked about.
Thank you so much for your continuing help!
I am determined to get to the bottom of this!
CAG